Center pull tab plug with sealing flange

ABSTRACT

A center pull tab sealing plug for sealing a hole in a structural member is provided, comprising a base element having top and bottom portions; a flexible flange extending from a periphery of the base element, the flange including at least one annular ridge or O-ring extending downwardly from a bottom surface of the flange and spaced from a side wall of the base element; and a pull tab extending upwardly from the top portion of the base element a distance sufficient to provide a gripping surface.

BACKGROUND OF THE INVENTION

The present invention is directed to a center pull tab plug having a sealing flange.

Center pull tab plugs are known. U.S. Pat. No. 3,148,798 discloses protective closure caps comprised of a generally frusto-conical cup-shaped plug having a flat rim extending outwardly therefrom. The plug may be used as a dust and moisture seal as a shipping protector for threads, pipe, tubing ends, etc. The plug may also be used as a masking device for electroplating and spray painting, as well as any other use which requires a bore or hole in an object to be temporarily sealed.

The center pull tab plug has met with much success in the marketplace. The plug is both easily used, and easily removed after use, due to the center pull tab.

The center pull tab plug is comprised of a relatively soft, flexible polymeric material to ensure good flexibility and fit during use. While the outwardly extending flat rim serves to assist in the sealing function during use, the rim functions primarily as a stop to prevent insertion of the plug into the hole or bore to be plugged to an extent greater than desired. While some sealing function is served by the rim, the degree of sealing is related to the lateral extent of the rim, as well as the degree to which the rim engages with the supporting surface.

Thus, a need exists to provide a center pull tab sealing plug that exhibits an enhanced sealing function in relation to the rim that extends laterally therefrom.

OBJECTS AND SUMMARY OF THE INVENTION

It is thus an object of the present invention to provide a center pull tab plug which exhibits enhanced sealing during use as a plug for a bore or hole in an object.

In accordance with the present invention, there is thus provided a center pull tab sealing plug for sealing a bore or hole in a structural member, comprising:

a base element having top and bottom portions;

a flexible flange extending from a periphery of the base element, the flange including at least one annular ridge or O-ring extending downwardly from a bottom surface of the flange and spaced from a side wall of said base element; and

a pull tab extending upwardly from said top portion of the sealing plug to an extent sufficient to serve as a gripping member.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of one embodiment of a center tab pull plug according to the present invention.

FIG. 2 is a cross-sectional view of the center tab pull plug of FIG. 1.

FIG. 3 is a view in detail of a portion of the cross-sectional view of FIG. 2.

FIG. 4 is a top view of the center pull tab plug of FIG. 1.

FIG. 5 depicts an alternative embodiment of the center pull tab plug of the present invention.

FIG. 6 is a cross-sectional view of the center tab pull plug of FIG. 5.

DETAILED VIEW OF THE PRESENT INVENTION

The center tab pull plug of the present invention will be described in relation to the Figures.

As shown in FIG. 1, the center tab pull plug 1 of the present invention is a generally frusto-conically shaped device comprised of a center pull tab 3, side wall 5, bottom wall 7, and outwardly extending flange 9.

The device of FIG. 1 has a closed bottom portion 11, and an open top portion 13. The center pull tab 3 extends into the interior of the plug and is integrally formed with or attached to the bottom of an interior cavity of the plug. The center pull tab extends upwardly from the interior of the plug a sufficient distance above the flange 9 to permit grasping of the tab by the user of the plug.

The pull tab extends from side-to-side within the interior of the plug cavity to enhance dimensional stability of the plug body. The portion of the pull tab within the plug cavity may be generally rectangular in shape, with the sides of the pull tab being attached to the interior wall by web portions 19 which extend outwardly from the pull tab to the side walls. The web portions may terminate at a point coextensive with the rim of the plug body, or somewhat below the rim.

The diameter of the bottom portion of the plug will preferably be less than the diameter of the top portion of the plug to assist in use of the plug. A decreased diameter for the bottom portion assists in initially seating the plug in the hole or bore to be sealed, as well as assisting in insertion of the plug into the hole or bore for a sufficient distance. The degree of taper of the plug body from the top of the plug body to the bottom of the plug body is preferably 2.5-7.5 degrees relative to the axis of the wall, with a degree of taper of 5 degrees having been found to be acceptable.

A flange 9 extends laterally from a top portion of the plug. The flange 9 preferably extends outwardly from the upper edge of the plug, although this is not critical.

The flange may extend outwardly from said plug body in a relatively perpendicular orientation to the plug body as shown in FIGS. 5 and 6. Alternatively, the flange may extend at a downwardly-oblique angle relative to the side wall of the plug as shown in FIGS. 1-3.

A bottom surface 15 of the flange includes at least one annular ridge or O-ring 17 that extends downwardly from the bottom surface of the flange. Annular ridges or O-rings are shown on the bottom surface of the flanges in FIGS. 2, 3 and 6.

The annular ridge or O-ring is spaced from the side wall of the plug, and may be either co-extensive with the outermost edge of the flange, or positioned between the end of the flange and the side wall of the plug. Advantageously, multiple ridges or O-rings may be positioned along the bottom surface of the flange. The number and size of the ridge or O-ring depends upon the size of the flange, which in turn depends upon the size of the plug. Of course, a flange of larger dimension will permit a greater number of ridges or O-rings to be employed.

The advantages provided by the above design of the flange are several.

The presence of the annual ridge(s) or O-ring(s) ensures that a tight seal is maintained as the ridge(s) or O-ring(s) are pressed against the top surface of the object to be sealed. The presence of multiple ridges or O-rings serves to additionally ensure that, if one fails to provide a satisfactory seal, then additional ones may still provide the desired sealing function.

The fact that the flange may be oriented in an orientation downwardly-oblique to the side wall of the plug ensures, when the plug is inserted into a bore or hole to be sealed, that the flange will be snugly fit against the surrounding top surface due to the flange being flexed or biased upwardly as it is seated against the top surface. The flange will accordingly be in a state of continual flex against the top surface, thus assisting in the formation of a secure seal.

The flange and attached ridges or O-rings may be of any suitable configuration. Advantageously, the flange may, when viewed in cross-section, taper or become thinner as it extends from the side wall of the plug as shown in FIG. 3. It is desirable for the flange at the junction with the side wall of the plug to be of sufficient thickness to resist the flexing or biasing of the flange upwardly when the plug is inserted into a hole or bore to be sealed. This is for the reason that downwardly-directed bias will then be maintained upon the flange during use to keep the flange in sealing contact with the top surface of the object to be sealed. Alternatively, the flange may be relatively constant in cross-section as it extends laterally from the side wall of the plug as shown in FIG. 6. The flange may be of constant or tapered cross-section irrespective of whether the flange extends perpendicularly or obliquely from the side wall of the plug.

The ridges or O-rings may have any convenient cross-sectional configuration. For example, a triangular configuration may be employed, with a tip of the triangle being positioned to contact the top surface of the object. Alternatively, the ridge or O-ring may have a rounded (or semi-circular) configuration which similarly contacts the top surface of the object. See FIG. 3 wherein both configurations are exemplified for the sake of illustration.

By way of exemplary dimensions, the thickness of the wall portion of the plug body may be in the range of about 0.025-0.040 inch, with the wall dimension depending upon the size of the plug body and the end use contemplated. The center pull tab portion may also range in diameter from 0.025 to 0.040 inch or so, with it also being possible for the diameter to diminish from the point of attachment of the pull tab at the bottom of the plug interior to the outermost end thereof.

For a plug which is configured to seal an open end of a 1.5 inch pipe, the plug may have a plug body of about 0.55 inch in length, a diameter of about 1.42 inch, a pull tab that extends about 0.40 inch from the top of the plug and is about 0.50 inch in width, with a flange extending about 0.15 inch from the side of the plug and being about 0.04 inch in thickness at its widest point adjacent the side wall of the plug. Annular ridges extending from the bottom surface of the flange are about 0.01 inch in height, and may be spaced about 0.04 inch apart.

By way of alternative embodiments, while the sealing plug of the present invention is depicted in FIGS. 1, 2 and 4 as having an interior cavity from which the center pull tab extends a distance sufficient to serve as a pull tab, it is not necessary for the plug to be hollow or to include such an interior cavity. The plug body may instead be solid, with the center pull tab extending from the top surface of the solid plug body, and with the annular flange still extending from a side wall of the plug body as shown in FIGS. 5 and 6.

However, it has been found to be advantageous for the plug body to have an interior cavity to reduce the cost of manufacture, as much less material is required when the interior is hollow. Otherwise, the hollow or solid plugs function equivalently in the desired sealing function.

The plug body can be formed from any conventional polymeric material which provides the requisite balance of physical stability and flexibility. Any conventional moldable polymer such as flexible polymeric materials can be used as the raw material for the plug body of the present invention. Thermoplastic rubber or elastomeric materials are preferred to permit adequate flexibility when being inserted into a cavity for sealing, while maintaining desired resilience for purposes of sealing. Such materials are well known in the art and one of ordinary skill in the art can readily select an appropriate material for use in the present invention.

The plug may be made by any conventional molding process, with the method of manufacture being well within the skill of the practitioner in the art. 

1. A center pull tab sealing plug for sealing a hole in a structural member, comprising: a base element having top and bottom portions; a flexible flange extending from a periphery of said base element, said flange including at least one annular ridge or O-ring extending downwardly from a bottom surface of said flange and spaced from a side wall of said base element; and a pull tab extending upwardly from said top portion of said base element a distance sufficient to provide a gripping surface.
 2. The sealing plug of claim 1, comprising multiple annular ridges or O-rings disposed along the bottom surface of said flange.
 3. The sealing plug of claim 1, wherein said at least one ridge or O-ring is triangular in cross-section.
 4. The sealing plug of claim 3, wherein said at least one ridge or O-ring is semi-circular in cross-section.
 5. The sealing plug of claim 1, comprising a cavity extending through a portion of said base element from the upper portion of said sealing plug to an interior bottom portion.
 6. The sealing plug of claim 5, wherein said pull tab extends upwardly from the said base element from a bottom portion of said plug within said cavity.
 7. The sealing plug of claim 1, wherein the body of said base element is solid.
 8. The sealing plug of claim 1, wherein the body of said base element includes a cavity extending from a top portion to an interior bottom portion.
 9. The sealing plug of claim 1, wherein said flange extends in an oblique angular relationship to said side wall of said base element
 10. The sealing plug of claim 9, comprising multiple annular ridges or O-rings disposed along the bottom surface of said flange.
 11. The sealing plug of claim 9, wherein said at least one ridge or O-ring is triangular in cross-section.
 12. The sealing plug of claim 11, wherein said at least one ridge or O-ring is semi-circular in cross-section.
 13. The sealing plug of claim 9, comprising a cavity extending through a portion of said base element from said upper portion of said base element to an interior bottom portion.
 14. The sealing plug of claim 13, wherein said pull tab extends upwardly from the top portion of said base element from a bottom portion of said base element within said cavity.
 15. The sealing plug of claim 9, wherein the body of said base element is solid.
 16. The sealing plug of claim 9, wherein the body of said base element includes a cavity extending from a top portion to an interior bottom portion. 